> Very low latency: 3.620 milliseconds round trip at 48 kHz with 64 sample buffer

"very low latency" in audio is <=1ms. 3.6ms is good but not special.

Round trip latency for RME devices (widely considered the best in the industry) is around 3ms, so this is indeed "very low latency".

You might be thinking of latency of the converters, which is normally sub-ms.

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alowell 29 minutes ago | parent | prev | next [-]

Check out the round trip latency measurements for audio interfaces on Linux here:

https://interfacinglinux.com/linux-compatible-audio-interfac...

AFAIK the best one is RME AIO Pro PCIe card. ETH-68 matches the round trip audio latency of this card at 48 kHz and surpasses it be 0.33 ms at 96 kHz.

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h3lp 3 hours ago | parent | prev | next [-]

They quote a roundtrip of 3.6ms, so one-way 1.8ms. In the plots on their page, it looks like the processing latency is centered on around 1ms:

> The LATMON pulse width is therefore an accurate measure of the total processing latency of each cycle and is affected by every element in the data path: processing delay in the microcontroller, network transmission delay, host OS delays, signal processing delay in the DAW, etc

	▲	alowell 25 minutes ago \| parent [-]
		You are confusing the audio latency with the processing latency. I see this mistake a lot. One way audio latency is about 3.6 ms divided by two = 1.8 ms. This type of latency is audible. Processing latency is just the amount of time it takes to complete all processing for each audio cycle. From the histograms, the typical processing latency is about 625 us and of course there is some jitter (almost all of the jitter comes from the Linux host BTW). Processing latency is not audible. However if the processing latency exceeds the deadline on a given audio cycle, there will be an underrun which will cause an audible glitch.

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k_roy 2 hours ago | parent | prev [-]

But it’s matching AND exceeding the performance of a $999 PCIe card designed for a similar purpose.

I would love to know why this is hand-wavy and not very cool? Even as not-audiophile, I’ve got ideas of things to use this for.

> RME HDSPe AIO Pro PCIe

> eth68 matches the latency performance of the RME card at 48 kHz and surpasses it by 0.33 ms at 96 kHz.

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Venn1 2 hours ago | parent [-]

As the owner of the PCIe card that measurement was taken from, yes, I’d say it’s quite impressive. The average round-trip latency for a USB audio interface at 48 kHz/128 samples would usually fall somewhere around 8 ms, which is a bit much if you’re monitoring post-FX.

On Linux, we don’t have much in the way of Thunderbolt support for audio interfaces, so the only way to achieve this sort of latency has traditionally been with PCIe or PCI audio interfaces. Having a low-cost, infinitely more portable solution would be very welcome.

	▲	k_roy 2 hours ago \| parent [-]
		Awesome. Love to see it! This is just the answer I was looking for. I definitely don’t know anything about the audio space, but am into networking hardcode. I love seeing audiophile projects that don’t involve a rebranded tp-link switch and marked up 1000%